1. Technical Field
The present invention relates to an image forming technique and information processing technique which can speed up the processing from the decryption of print data at the start of printing to the execution of printing while ensuring confidentiality on a network and the confidentiality of print data in an image forming apparatus which processes the data by encrypting the print data.
2. Background Art
Recently, printing systems in which printing apparatuses are shared through networks or the like have increased in number. When a plurality of users use a printing apparatus through a network or the like, the users who have input print jobs are distant from the printing apparatus at the start of printing in many cases. The printed output data may be exposed to a third party. That is, confidentiality cannot be maintained.
As a printing apparatus for which measures are taken to prevent printed output data from being exposed to a third party, an apparatus has been proposed, in which a client computer generates a print job with a personal identification number or password in accordance with, for example, an operation performed by the user who has input the print job, and a printing apparatus executes the print job. Upon receiving the print job with the personal identification number or password from the client computer, the printing apparatus temporarily stores the print job in a storage medium such as a memory or hard disk in the apparatus. When the user who has input the print job walks to the printing apparatus afterward and inputs a personal identification number or password through the operation panel of the printing apparatus, the input personal identification number or password is collated with that of the print job. If the printing apparatus determines in accordance with the collation result that the correct password or the like has been input, the printing apparatus starts executing the stored print job. In this case, since printing is started after the user who has input the print job walks to the printing apparatus, there is no chance that the printed output data of the user will be exposed to a third party (see, for example, Japanese Patent Laid-Open No. 11-212744).
In addition, in order to start printing in front of the printing apparatus, the user must specify a target print job. In general, a print job list is displayed on the display screen of the operation panel of the printing apparatus to let the user select a target print job, and the user inputs a password or the like to make the printing apparatus start printing. Instead of using this method, i.e., letting the user select a print job and input a password or the like, a method using an ID card to improve the convenience of the user has been proposed. In this method, ID information registered in an ID card is used as a personal identification number or password. When this ID card is inserted into the printing apparatus, the printing apparatus reads out the ID information, and finds out a print job with a personal identification number or the like of the print job, stored in the printing apparatus, which coincides with the readout ID information, thereby performing printing operation (see, for example, Japanese Patent Laid-Open No. 11-150559).
There is a risk that print data exchanged through a network will be monitored on the network and duplicated by a third party, and the third party will duplicate and obtain the contents of the print job without permission by transmitting the duplicated print data to another printing apparatus. There is also a risk that a third party will duplicate the data of a print job itself stored in the printing apparatus, and transmit the data to another printing apparatus, thus duplicating and obtaining the contents of the print job without permission.
In order to cope with such a problem, there has been proposed a system which encrypts print data exchanged through a network and print data stored in a printing apparatus (see, for example, Japanese Patent Laid-Open No. 09-134264).
In addition, recently, IC cards have increasingly become popular, and studies have been made on the use of an IC card instead of the above ID card which is used to simplify the operation of inputting a personal identification number or password. An improvement in the performance of IC cards allows the IC cards to perform the above encryption by themselves. This makes it basically impossible to perform decryption without an IC card which has been used for encryption. Therefore, stricter methods of protecting print data have been studied.
In a printing operation in which the confidentiality of print data is protected by using IC cards, in general, decryption can be performed only by an IC card which has been used for encryption, and hence printing processing cannot be started until the IC card is inserted into a printing apparatus in which encrypted print data is stored. Print data is written by a page description language and the like, and the printing apparatus prints after converting the print data expressed by the page description language and the like into image data. That is, the print data cannot be converted into image data until the user inserts an IC card into the printing apparatus. Therefore, it takes much time to convert print data written by a complex page description language into image data. That is, it takes much time to deliver printed matter after the user inserts an IC card.
The present invention has been made in consideration of the above problem, and has as its object to provide an image forming apparatus, image forming method, and the like which can speed up the processing from the decryption of data at the start of printing to the execution of printing while ensuring confidentiality on a network and the confidentiality of print, data in the image printing apparatus which processes the print data by encrypting the print data.